That’s easy, life and mistakes.
I learned way more from mistakes than I did from successes. I expected them. Having to re-do something, or being embarrassed for saying or doing the wrong thing, were lessons I never forgot. For the record, I consider losing the same thing as a mistake. I hate to lose at anything. If I do, I make sure it only happens once in a row,.
Life is a great teacher. When you get old like me, you’ve been through a lot. School can’t teach you much other than how to learn, or some facts to memorize. Having to survive is a lesson that I get every day. Hell, I’m grateful every day I wake up now.
Delusions of Adequacy 